Continuously variable transmission

ABSTRACT

Inventive embodiments are directed to components, subassemblies, systems, and/or methods for continuously variable transmissions (CVT). In one embodiment, a control system is adapted to facilitate a change in the ratio of a CVT. In another embodiment, a control system includes a stator plate configured to have a plurality of radially offset slots. Various inventive traction planet assemblies and stator plates can be used to facilitate shifting the ratio of a CVT. In some embodiments, the traction planet assemblies include planet axles configured to cooperate with the stator plate. In one embodiment, the stator plate is configured to rotate and apply a skew condition to each of the planet axles. In some embodiments, a stator driver is operably coupled to the stator plate. Embodiments of a traction sun are adapted to cooperate with other components of the CVT to support operation and/or functionality of the CVT. Among other things, shift control interfaces for a CVT are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/062,461, filed Mar. 7, 2016 and scheduled to issue as U.S. Pat. No.9,920,823 on Mar. 20, 2018, which is a continuation of U.S. patentapplication Ser. No. 14/195,483, filed Mar. 3, 2014 and issued as U.S.Pat. No. 9,279,482 on Mar. 8, 2016, which is a continuation of U.S.patent application Ser. No. 13/717,197, filed Dec. 17, 2012 and issuedas U.S. Pat. No. 8,663,050 on Mar. 4, 2014, which is a continuation ofU.S. patent application Ser. No. 12/760,823, filed Apr. 15, 2010 andissued as U.S. Pat. No. 8,360,917 on Jan. 29, 2013, which claims thebenefit of U.S. Provisional Application 61/170,073, filed on Apr. 16,2009, U.S. Provisional Application 61/234,905, filed on Aug. 18, 2009,and U.S. Provisional Application 61/239,377, filed on Sep. 2, 2009. Thedisclosures of U.S. patent application Ser. No. 12/760,823, U.S. patentapplication Ser. No. 13/717,197, U.S. patent application Ser. No.14/195,483, and U.S. patent application Ser. No. 15/062,461 are herebyincorporated by reference in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The field of the invention relates generally to transmissions, and moreparticularly to methods, assemblies, and components for continuouslyvariable transmissions (CVTs).

Description of the Related Art

There are well-known ways to achieve continuously variable ratios ofinput speed to output speed. Typically, a mechanism for adjusting thespeed ratio of an output speed to an input speed in a CVT is known as avariator. In a belt-type CVT, the variator consists of two adjustablepulleys coupled by a belt. The variator in a single cavity toroidal-typeCVT usually has two partially toroidal transmission discs rotating abouta shaft and two or more disc-shaped power rollers rotating on respectiveaxes that are perpendicular to the shaft and clamped between the inputand output transmission discs. Usually, a control system is used for thevariator so that the desired speed ratio can be achieved in operation.

Embodiments of the variator disclosed here are of the spherical-typevariator utilizing spherical speed adjusters (also known as poweradjusters, balls, planets, sphere gears, or rollers) that each has atiltable axis of rotation adapted to be adjusted to achieve a desiredratio of output speed to input speed during operation. The speedadjusters are angularly distributed in a plane perpendicular to alongitudinal axis of a CVT. The speed adjusters are contacted on oneside by an input disc and on the other side by an output disc, one orboth of which apply a clamping contact force to the rollers fortransmission of torque. The input disc applies input torque at an inputrotational speed to the speed adjusters. As the speed adjusters rotateabout their own axes, the speed adjusters transmit the torque to theoutput disc. The output speed to input speed ratio is a function of theradii of the contact points of the input and output discs to the axes ofthe speed adjusters. Tilting the axes of the speed adjusters withrespect to the axis of the variator adjusts the speed ratio.

There is a continuing need in the industry for variators and controlsystems therefor that provide improved performance and operationalcontrol. Embodiments of the systems and methods disclosed here addresssaid need.

SUMMARY OF THE INVENTION

The systems and methods herein described have several features, nosingle one of which is solely responsible for its desirable attributes.Without limiting the scope as expressed by the claims that follow, itsmore prominent features will now be discussed briefly. After consideringthis discussion, and particularly after reading the section entitled“Detailed Description of Certain Inventive Embodiments” one willunderstand how the features of the system and methods provide severaladvantages over traditional systems and methods.

One aspect of the invention concerns a stator assembly for acontinuously variable transmission (CVT) having a number of tractionplanet assemblies arranged about a longitudinal axis of the CVT. In oneembodiment, the CVT includes a first stator coupled to the tractionplanet assemblies. The first stator has a number of radial guide slots.The CVT includes a second stator coupled to the traction planetassemblies. The second stator has a number of radially offset guideslots configured to guide the traction planet assemblies. In oneembodiment, the CVT includes a reaction plate coupled to the tractionplanet assemblies. The CVT can be provided with a number of eccentricgears coupled to the first stator. The CVT includes a stator drivercoupled to the eccentric gears. The second stator is adapted to rotatewith respect to the first stator.

One aspect of the invention relates to a continuously variabletransmission (CVT) having a number of traction planets arrangedangularly about a longitudinal axis of the CVT. In one embodiment, theCVT has a first stator coupled to the each of the traction planetassemblies. The first stator has a number of radially off-set slots. Thefirst stator is configured to guide the traction planet assemblies. TheCVT also includes a stator driver assembly coupled to the first stator.The stator driver assembly is coaxial to the first stator.

Another aspect of the invention concerns a stator driver assembly for acontinuously variable transmission (CVT) having a group of tractionplanet assemblies. The stator driver assembly includes a shift tube anda gear set coupled to the shift tube. In one embodiment, the statordriver assembly includes a stator coupled to the gear set. The statorhas a number of radially off-set guide slots adapted to couple to thetraction planet assemblies. In one embodiment, a rotation of the shifttube corresponds to a rotation of the stator.

Another aspect of the invention concerns a stator assembly for acontinuously variable transmission (CVT) having a number of tractionplanet assemblies. In one embodiment, the stator assembly includes afirst stator having a number of radial slots. The stator assemblyincludes a second stator coaxial with the first stator. The first andsecond stators are configured to rotate relative to each other. Thesecond stator has a number of radially off-set guide slots. In oneembodiment, the stator assembly includes a reaction member that iscoaxial with the first and second stators. The stator assembly includesa number of eccentric gears coupled to the reaction member and the firststator. The stator assembly also includes a stator driver coupled toeach of the eccentric gears.

Another aspect of the invention relates to a shifting mechanism for acontinuously variable transmission (CVT) provided with a number oftraction planet assemblies. In one embodiment, the shifting mechanismincludes a shift tube aligned with a longitudinal axis of the CVT. Theshifting mechanism can be provided with a shift arm operably coupled tothe shift tube. The shift arm has a first guide slot. The shiftingmechanism includes a reaction arm coupled to a main shaft of the CVT.The reaction arm has a second guide slot. In one embodiment, theshifting mechanism includes a cable coupled to the shift arm and thereaction arm. The cable has a cable end configured to be received in thefirst and second guide slots. The shift arm is adapted to rotate withrespect to the reaction arm.

Another aspect of the invention concerns a shifting mechanism for acontinuously variable transmission (CVT) having a skew-based controlsystem. The shifting mechanism includes a shift arm operably coupled tothe skew-based control system. In one embodiment, the shifting mechanismincludes a transfer gear coupled to the shift arm. The transfer gear hasan eccentric guide bore configured to engage the shift arm. The shiftingmechanism includes an input gear coupled to the transfer gear. The inputgear is configured to rotate the transfer gear. The input gear and thetransfer gear are attached to a rigid member.

Another aspect of the invention relates to a shifting mechanism for acontinuously variable transmission (CVT) having a stator driver. In oneembodiment, the shifting mechanism includes a pulley operably coupled tothe stator driver. The pulley has a splined bore. The pulley has acable-end attachment interface. The shifting mechanism includes areaction arm operably coupled to a main shaft of the CVT. The reactionarm is configured to receive a cable. The reaction arm is configured tooperably couple to the pulley.

Yet one more aspect of the invention addresses a shifting mechanism fora continuously variable transmission (CVT) having a skew-based controlsystem. The shifting mechanism includes a reaction arm coupled to a mainshaft of the CVT. In one embodiment, the shifting mechanism includes ashift arm operably coupled to the skew-based control system. The shiftarm is configured to rotate with respect to the reaction arm. Theshifting mechanism has a first lever coupled to the shift arm. Theshifting mechanism has a cable coupled to the first lever. The shiftingmechanism also has a linkage coupled to the first lever.

In another aspect, the invention concerns a shifting mechanism for acontinuously variable transmission (CVT) having a group of tractionplanet assemblies. In one embodiment, the shifting mechanism includes atleast one cable. The shifting mechanism has a pulley operably coupled tothe cable. The pulley is adapted to translate and rotate. In oneembodiment, the shifting mechanism includes a reaction member operablycoupled to the pulley. The reaction member has a pocket configured toreceive a spring. The shifting mechanism includes a roller coupled tothe pulley. The roller is adapted to contact the spring.

One aspect of the invention relates to a continuously variabletransmission (CVT) having a group of traction planet assemblies arrangedabout a longitudinal axis of the CVT. The CVT has a first stator coupledto the traction planet assemblies. The first stator has a group ofradially off-set guide slots. The guide slots are adapted to couple tothe traction planet assemblies. In one embodiment, the CVT includes asecond stator coupled to the traction planet assemblies. The secondstator is coaxial with the first stator. The CVT has a reaction membercoupled to the first and second stators. The CVT also has a guide memberoperably coupled to the second stator. The guide member is configured torotate the second stator with respect to the first stator.

Another aspect of the invention relates to a shifting mechanism for acontinuously variable transmission (CVT) having a group of tractionplanet assemblies. In one embodiment, the shifting mechanism includes astator having radially off-set guide slots. The shifting mechanism canhave a spring coupled to the stator. In one embodiment, the shiftingmechanism has a reaction arm coupled to the spring. The shiftingmechanism has a shift tube coupled to the stator and a push link coupledto the shift tube. In one embodiment, the shifting mechanism has firstand second linkages coupled to the push link. The first linkage iscoupled to the stator. The second linkage is coupled to the reactionarm.

Yet one more aspect of the invention addresses a shifting mechanism fora continuously variable transmission (CVT) having a group of tractionplanet assemblies. In one embodiment, the shifting mechanism has astator having radially off-set guide slots. The shifting mechanism caninclude a pin coupled to the stator. In one embodiment, the shiftingmechanism includes a driven gear coupled to the stator. The driven gearhas a slot configured to receive the pin. The shifting mechanism canalso include a driver coupled to the driven gear. The driver isconfigured to rotate the driven gear to facilitate a rotation of thestator.

One aspect of the invention concerns a shifting mechanism for acontinuously variable transmission (CVT). In one embodiment, theshifting mechanism includes a main shaft provided with a first set ofhelical grooves formed about an outer circumference. The shiftingmechanism includes a stator having a second set of helical groovesformed on an inner circumference. The stator has a number of radiallyoff-set slots. In one embodiment, the shifting mechanism includes ashift tube coaxial with the stator. The shifting mechanism can alsoinclude a number of rollers coupled to the shift tube. The rollers areconfigured to contact the first and second helical grooves.

One aspect of the invention relates to a continuously variabletransmission (CVT) having a group of traction planet assemblies. In oneembodiment, the CVT is provided with a first stator having a number ofradially offset slots. The CVT has a second stator having a number ofradial slots. The CVT includes a shift tube coaxial with the first andsecond stators. The CVT also includes a number of rollers coupled to theshift tube.

Another aspect of the invention concerns a continuously variabletransmission (CVT) having a number of traction planet assemblies. In oneembodiment, the CVT includes a first stator coupled to the tractionplanet assemblies. The CVT has a second stator coupled to the tractionplanet assemblies. The second stator is coaxial with the first stator.The second stator is configured to rotate with respect to the firststator. The CVT is also provided with a fly-ball governor coupled to thefirst stator.

Yet another aspect of the invention involves a control system forcontinuously variable transmission (CVT) having a group of tractionplanet assemblies coupled to a stator. In one embodiment, the controlsystem includes a hydraulic control valve supplied with a pressurizedfluid. The hydraulic control valve is adapted to couple to the stator.The control system can have an orifice in fluid communication with thehydraulic control valve. A change in the pressurized fluid correspondsto a change in the rotational position of the stator.

One aspect of the invention concerns a continuously variabletransmission (CVT) having a number of traction planet assemblies. In oneembodiment, the CVT has a first stator coupled to the traction planetassemblies. The CVT includes a second stator coupled to the tractionplanet assemblies. The second stator is coaxial with the first stator.The second stator is configured to rotate with respect to the firststator. The second stator has a number of radially off-set guide slots.The first and second stators are adapted to receive a rotational power.The CVT also includes a planetary gear set coupled to the first stator.The planetary gear set is configured to facilitate a relative rotationbetween the first and second stators.

In another aspect, the invention concerns a shifting mechanism for acontinuously variable transmission (CVT) having a number of tractionplanet assemblies coupled to first and second stators. The shiftingmechanism includes a stator driver operably coupled to the first stator.In one embodiment, the shifting mechanism includes a pulley having asplined inner bore. The shifting mechanism has a number of planet gearscoupled to the inner bore of the pulley. The shifting mechanism also hasa reaction arm operably coupled to a main shaft of the CVT. In oneembodiment, the shifting mechanism has a sun gear coupled to thereaction arm. The sun gear is coupled to each planet gear. The shiftingmechanism can have a cage coupled to the planet gears. The cage has asplined inner bore coupled to the stator driver. The pulley is adaptedto receive first and second control cables.

Another aspect of the invention relates to a stator for a continuouslyvariable transmission (CVT) having a number of traction planetassemblies. In one embodiment, the stator includes a disc-shaped bodyhaving a central bore. The stator has a number of guide slots formed ona first side of the disc-shaped body. The guide slots are arrangedangularly about the central bore. Each guide slot is radially offsetwith respect to the center of the disc-shaped body.

One more aspect of the invention relates to a planocentric gear sethaving a fixed ring arranged along a longitudinal axis. In oneembodiment, the planocentric gear set has an output ring coaxial withthe fixed ring. The gear set includes an orbital planet gear having afirst gear ring and a second gear ring. The first gear ring has a largerdiameter than the second gear ring. The orbital planet gear has acentral bore. The gear set also includes an eccentric driver coaxialwith the fixed ring and the output ring. The eccentric driver has aneccentric lobe surface adapted to couple to the inner bore of theorbital planet gear.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of a ball planetary continuously variabletransmission (CVT) having a skew-based control system.

FIG. 2 is an exploded perspective view of the CVT of FIG. 1.

FIG. 3 is a cross-sectional view of the CVT of FIG. 1.

FIG. 4 is a cross-sectional perspective view of certain components ofthe CVT of FIG. 1.

FIG. 5 is an exploded, cross-sectional, perspective view of certaincomponents of the CVT of FIG. 1.

FIG. 6 is a perspective view of a first stator that can be used with theCVT of FIG. 1.

FIG. 7 is another perspective view of the first stator of FIG. 6.

FIG. 8 is a plan view of the first stator of FIG. 6.

FIG. 8A is a plan view (detail view A) of one embodiment of a radiallyoff-set slot that can be provided on the first stator of FIG. 6.

FIG. 9 is a cross-sectional view of the first stator of FIG. 6.

FIG. 10 is a perspective view of a second stator that can be used withthe CVT of FIG. 1.

FIG. 11 is another perspective view of the second stator of FIG. 10.

FIG. 12 is a plan view of the second stator of FIG. 10.

FIG. 13 is a cross-sectional view of the second stator of FIG. 10.

FIG. 14 is a perspective view of a timing plate that can be used withthe CVT of FIG. 1.

FIG. 15 is a cross-sectional perspective view of the timing plate ofFIG. 14.

FIG. 16 is a Detail View B of the timing plate of FIG. 14.

FIG. 17 is a perspective view of a stator driver assembly that can beused with the CVT of FIG. 1.

FIG. 18 is an exploded perspective view of the stator driver assembly ofFIG. 17.

FIG. 19 is a perspective view of an embodiment of a stator driverassembly.

FIG. 20 is an exploded perspective view of the stator driver assembly ofFIG. 19.

FIG. 21 is a perspective view of another embodiment of a stator driverassembly.

FIG. 22 is an exploded perspective view of the stator driver assembly ofFIG. 21.

FIG. 23 is a cross-sectional view of an embodiment of a CVT having askew-based control system.

FIG. 24 is an exploded, cross-sectional perspective view of the CVT ofFIG. 23.

FIG. 25 is a perspective view of certain components of the CVT of FIG.23.

FIG. 26 is a cross-sectional perspective view of certain components ofthe CVT of FIG. 23.

FIG. 27A is an exploded, cross-sectional perspective view of certaincomponents of the CVT of FIG. 23.

FIG. 27B is a plan view of an eccentric gear that can be used with theCVT of FIG. 23.

FIG. 27C is a perspective view of a sliding block and the eccentric gearof FIG. 27.

FIG. 28 is a perspective view of a shifting mechanism that can be usedwith the CVT of FIG. 1 or FIG. 23.

FIG. 29 is an exploded perspective view of the shifting mechanism ofFIG. 28.

FIG. 30 is a perspective view of an embodiment of a shifting mechanismthat can be used with the CVT of FIG. 1 or 23.

FIG. 31 is a perspective view of another embodiment of a shiftingmechanism that can be used with the CVT of FIG. 1 or 23.

FIG. 32 is a perspective view of yet another embodiment of a shiftingmechanism that can be used with the CVT of FIG. 1 or 23.

FIG. 33 is an exploded perspective view of the shifting mechanism ofFIG. 32.

FIG. 34 is a schematic illustration of an embodiment of a shiftingmechanism that can be used with the CVT of FIG. 1 or 23.

FIG. 35 is a schematic illustration of another embodiment of a shiftingmechanism that can be used with the CVT of FIG. 1 or 23.

FIG. 36 is a schematic illustration of a shifting mechanism and handlegrip that can be used with the CVT of FIG. 1 or 23.

FIG. 37A is a plan view illustration of a first position of the shiftingmechanism of FIG. 36.

FIG. 37B is a plan view illustration of a second position of theshifting mechanism of FIG. 36.

FIG. 38 is a partial cross-section view of certain components of anembodiment of a CVT having a skew-based control system.

FIG. 39 is a plan view of a shifting mechanism that can be used with theCVT of FIG. 38.

FIG. 40 is a schematic illustration of an embodiment of a shiftingmechanism that can be used with a CVT having a skew-based controlsystem.

FIG. 41 is a schematic illustration of another embodiment of a shiftingmechanism that can be used with a CVT having a skew-based controlsystem.

FIG. 42 is a schematic illustration of an embodiment of a shiftingmechanism that can be used with a CVT having a skew-based controlsystem.

FIG. 43 is a section A-A view of the shifting mechanism of FIG. 42.

FIG. 44 is a schematic illustration of another embodiment of a shiftingmechanism that can be used with a CVT having a skew-based controlsystem.

FIG. 45 is a schematic illustration of a CVT having a skew-based controlsystem and a fly-ball governor.

FIG. 46A is a schematic illustration of a CVT having a skew-basedcontrol system and a speed governor and a torque governor.

FIG. 46B is a schematic illustration of a CVT having a skew-basedcontrol system and a speed governor and a torque governor.

FIG. 47 is a schematic illustration of a hydraulic control system thatcan be used with a CVT having a skew-based control system.

FIG. 48 is a schematic of certain components of a bicycle employing aCVT having a skew-based control system.

FIG. 49 is a partial, cross-sectional perspective view of an embodimentof a CVT employing a skew-based control system.

FIG. 50 is a cross-sectional view of the CVT of FIG. 49.

FIG. 51 is a partial, cross-sectional perspective view of anotherembodiment of a CVT employing a skew-based control system.

FIG. 52 is a cross-sectional view of the CVT of FIG. 51.

FIG. 53 is a schematic view of an embodiment of a CVT having askew-based control system and a planetary gear set.

FIG. 54 is a schematic view of an embodiment of a CVT having askew-based control system and an actuator shaft.

FIG. 55 is a partial cross-sectional view of a CVT having a skew-basedcontrol system and an internal freewheel mechanism.

FIG. 56 is section view B-B of the CVT of FIG. 55.

FIG. 57 is a detail view A of the CVT of FIG. 55.

FIG. 58 is an alternative embodiment of a freewheel spring that can beused with the CVT of FIG. 55.

FIG. 59 is a schematic illustration of a hydraulic control system thatcan be used with a CVT having a skew-based control system.

FIG. 60 is another schematic illustration of a hydraulic control systemthat can be used with a CVT having a skew-based control system.

FIG. 61 is yet another schematic illustration of a hydraulic controlsystem that can be used with a CVT having a skew-based control system.

FIG. 62 is a perspective view of yet another embodiment of a shiftingmechanism that can be used with the CVT of FIG. 1, 23, or 55 forexample.

FIG. 63 is a perspective view of the shifting mechanism of FIG. 62.

FIG. 64 is an exploded perspective view of the shifting mechanism ofFIG. 62.

FIG. 65 is a partial cross-section view of the shifting mechanism andCVT of FIG. 62.

FIG. 66 is a partial cross-section perspective view of a traction planetcarrier assembly that can be used with the CVT of FIG. 1, 23, 55, or 62for example.

FIG. 67 is a perspective view of yet another embodiment of a shiftingmechanism that can be used with the CVT of FIG. 1, 23, or 55 forexample.

FIG. 68 is another perspective view of the shifting mechanism of FIG.67.

FIG. 69 is an exploded, perspective view of the shifting mechanism ofFIG. 67.

FIG. 70 is a cross-sectioned plan view of the shifting mechanism of FIG.67.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

The preferred embodiments will be described now with reference to theaccompanying figures, wherein like numerals refer to like elementsthroughout. The terminology used in the descriptions below is not to beinterpreted in any limited or restrictive manner simply because it isused in conjunction with detailed descriptions of certain specificembodiments of the invention. Furthermore, embodiments of the inventioncan include several inventive features, no single one of which is solelyresponsible for its desirable attributes or which is essential topracticing the inventions described. Certain CVT embodiments describedhere are generally related to the type disclosed in U.S. Pat. Nos.6,241,636; 6,419,608; 6,689,012; 7,011,600; 7,166,052; U.S. patentapplication Ser. Nos. 11/243,484 and 11/543,311; and Patent CooperationTreaty patent applications PCT/IB2006/054911, PCT/US2008/068929,PCT/US2007/023315, PCT/US2008/074496, and PCT/US2008/079879. The entiredisclosure of each of these patents and patent applications is herebyincorporated herein by reference.

As used here, the terms “operationally connected,” “operationallycoupled”, “operationally linked”, “operably connected”, “operablycoupled”, “operably linked,” and like terms, refer to a relationship(mechanical, linkage, coupling, etc.) between elements whereby operationof one element results in a corresponding, following, or simultaneousoperation or actuation of a second element. It is noted that in usingsaid terms to describe inventive embodiments, specific structures ormechanisms that link or couple the elements are typically described.However, unless otherwise specifically stated, when one of said terms isused, the term indicates that the actual linkage or coupling may take avariety of forms, which in certain instances will be readily apparent toa person of ordinary skill in the relevant technology.

For description purposes, the term “radial” is used here to indicate adirection or position that is perpendicular relative to a longitudinalaxis of a transmission or variator. The term “axial” as used here refersto a direction or position along an axis that is parallel to a main orlongitudinal axis of a transmission or variator. For clarity andconciseness, at times similar components labeled similarly (for example,washers 35A and washers 35B) will be referred to collectively by asingle label (for example, washers 35).

It should be noted that reference herein to “traction” does not excludeapplications where the dominant or exclusive mode of power transfer isthrough “friction.” Without attempting to establish a categoricaldifference between traction and friction drives here, generally thesemay be understood as different regimes of power transfer. Tractiondrives usually involve the transfer of power between two elements byshear forces in a thin fluid layer trapped between the elements. Thefluids used in these applications usually exhibit traction coefficientsgreater than conventional mineral oils. The traction coefficient (μ)represents the maximum available traction forces which would beavailable at the interfaces of the contacting components and is ameasure of the maximum available drive torque. Typically, frictiondrives generally relate to transferring power between two elements byfrictional forces between the elements. For the purposes of thisdisclosure, it should be understood that the CVTs described here mayoperate in both tractive and frictional applications. For example, inthe embodiment where a CVT is used for a bicycle application, the CVTcan operate at times as a friction drive and at other times as atraction drive, depending on the torque and speed conditions presentduring operation.

One aspect of the continuously variable transmissions disclosed hererelates to drive systems wherein a prime mover drives various drivendevices. The prime mover can be, for example, an electrical motor and/oran internal combustion engine. For purposes of description here, anaccessory includes any machine or device that can be powered by a primemover. For purposes of illustration and not limitation, said machine ordevice can be a power takeoff device (PTO), pump, compressor, generator,auxiliary electric motor, etc. Accessory devices configured to be drivenby a prime mover may also include alternators, water pumps, powersteering pumps, fuel pumps, oil pumps, air conditioning compressors,cooling fans, superchargers, turbochargers and any other device that istypically powered by an automobile engine. Usually, the speed of a primemover varies as the speed or power requirements change; however, in manycases the accessories operate optimally at a given, substantiallyconstant speed. Embodiments of the continuously variable transmissionsdisclosed here can be used to control the speed of the power deliveredto the accessories powered by a prime mover.

In other situations, inventive embodiments of the continuously variabletransmissions disclosed here can be used to decrease or increase speedand/or torque delivered to the accessories for achieving optimal systemperformance. In certain situations, inventive embodiments of thecontinuously variable transmissions disclosed here can be used toincrease speed to the accessories when the prime mover runs at low speedand to decrease speed to the accessories when the prime mover runs athigh speed. Thus, the design and operation of accessories can beoptimized by allowing the accessories to operate at one substantiallyfavorable speed, or a more narrow speed range whereby the accessoriesneed not be made larger than necessary to provide sufficient performanceat an optimal speed or speed range.

Embodiments of the invention disclosed here are related to the controlof a variator and/or a CVT using generally spherical planets each havinga tiltable axis of rotation (sometimes referred to here as a “planetaxis of rotation”) that can be adjusted to achieve a desired ratio ofinput speed to output speed during operation. In some embodiments,adjustment of said axis of rotation involves angular misalignment of theplanet axis in a first plane in order to achieve an angular adjustmentof the planet axis of rotation in a second plane, thereby adjusting thespeed ratio of the variator. The angular misalignment in the first planeis referred to here as “skew” or “skew angle”. In one embodiment, acontrol system coordinates the use of a skew angle to generate forcesbetween certain contacting components in the variator that will tilt theplanet axis of rotation in the second plane. The tilting of the planetaxis of rotation adjusts the speed ratio of the variator. Embodiments ofskew control systems (sometimes referred to here as “skew based controlsystems”) and skew angle actuation devices for attaining a desired speedratio of a variator will be discussed.

Embodiments of a continuously variable transmission (CVT), andcomponents and subassemblies thereof, will be described now withreference to FIGS. 1-70. FIG. 1 shows a CVT 10 that can be used in manyapplications including, but not limited to, human powered vehicles (forexample, bicycles), light electrical vehicles, hybrid human-, electric-,or internal combustion powered vehicles, industrial equipment, windturbines, etc. Any technical application that requires modulation ofmechanical power transfer between a power input and a power sink (forexample, a load) can implement embodiments of the CVT 10 in its powertrain.

Referring now to FIGS. 1-3, in one embodiment the CVT 10 includes ahousing 11 configured to structurally support and generally enclosescomponents of the CVT 10. The CVT 10 can be provided with a shiftingmechanism 12 configured to cooperate with, for example, a cable actuatorof a bicycle (not shown). In some embodiments, the CVT 10 has a sprocket14 configured to receive an input power. In one embodiment, the shiftingmechanism 12 includes a pulley 16 coupled to a shift tube 18.

Still referring to FIG. 3, in one embodiment of the CVT 10, an inputdriver 20 can be arranged coaxial with a main axle 22. The input driver20 can be configured to receive an input power from, for example, thesprocket 14 or other suitable coupling. In one embodiment, the inputdriver 20 is coupled to a torsion plate 24 that is coupled to a firstaxial force generator assembly 26. The axial force generator assembly 26is operably coupled to a first traction ring 28. The first traction ring28 is configured to contact each of a plurality of traction planets 30.Each traction planet 30 is in contact with an idler 31 located radiallyinward of the traction planets 30. A second traction ring 32 isconfigured to contact each of the traction planets 30. In oneembodiment, the second traction ring 32 is coupled to a second axialforce generator assembly 34. The second axial force generator assembly34 can be substantially similar to the first axial force generatorassembly 26. In certain embodiments, the axial force generatorassemblies 26, 34 can be substantially similar to the clamping forcegenerator mechanisms generally described in Patent Cooperation TreatyApplication PCT/US2007/023315, the entire disclosure of which is herebyincorporated herein by reference. In one embodiment, the CVT 10 can beprovided with a set of nuts 33 and washers 35A, 35B to facilitate thecoupling of the main axle 22 to, for example, a bicycle frame (notshown). The main axle 22 can further be coupled to the bicycle frame viaa reaction arm 37.

During operation of CVT 10, an input power can be transferred to theinput driver 20 via, for example, the sprocket 14. The input driver 20can transfer power to the first axial force generator 26 via the torsionplate 24. The first axial force generator 26 can transfer power to thetraction planets 30 via a traction or friction interface between thefirst traction ring 28 and the each of the traction planets 30. Thetraction planets 30 deliver the power to the housing 11 via the secondtraction ring 32 and the second axial force generator 34. A shift in theratio of input speed to output speed, and consequently, a shift in theratio of input torque to output torque, is accomplished by tilting therotational axis of the traction planets 30. In one embodiment, thetilting of the rotational axes of the traction planets 30 isaccomplished by rotating a first stator 36 with respect to a secondstator 38.

Referring now to FIGS. 4 and 5, each of the traction planets 30 isprovided with a planet axle 42 received in an inner bore. In someembodiments, the traction planet 30 is rotatable about the planet axle42. In other embodiments, the planet axle 42 is rotationally fixedrelative to the traction planet 30 so that the planet axle 42 and thetraction planet 30 rotate in unison. In one embodiment the CVT 10 can beprovided with a timing plate 40 operably coupled to one end of theplanet axles 42. The timing plate 40 facilitates the generalsynchronization of the traction planet assemblies 30. When the CVT 10 isnot operating, that is, when the traction planet assemblies 30 are notspinning, the timing plate 40 retains the traction planet assemblies 30to generally start near the same angular position upon operation of theCVT 10. However, during most operating conditions of the CVT 10, thetiming plate 40 is substantially passive in guiding the traction planetassemblies 30. The CVT 10 can be provided with a stator driver assembly44 coupled to the shift tube 18. The stator driver assembly 44 iscoupled to the first stator 36. The stator driver assembly 44 canfacilitate a rotation of the first stator 36 about a longitudinal axisof the CVT 10.

Passing now to FIGS. 6-9, in one embodiment the second stator 38 is asubstantially disc-shaped body 50 having a central bore 52. The centralbore 52 facilitates the coupling of the second stator 38 to the mainaxle 22. The disc-shaped body 50 can be provided with a plurality ofradially off-set curved guide slots 54 arranged angularly about thecentral bore 52. Each radially off-set guide slot 54 is sized toaccommodate the coupling of the second stator 38 to the planet axle 42.The radially off-set guide slots 54 are angularly offset from a radialconstruction line 56 when viewed in the plane of the page of FIG. 8. Theangular offset can be approximated by an angle 58. The angle 58 isformed between the radial construction line 56 and a construction line60. The construction line 60 substantially bisects the guide slot 54when viewed in the plane of the page of FIG. 8. In some embodiments, theangle 58 is between 3 degrees and 45 degrees. A low angle 58 wouldprovide faster shift rates in a given application but stator clockingangle (beta) must be controlled over a very small range. A high angle 58would provide slower shift rates in a given application but statorclocking angle (beta) would be controlled over a larger range. Ineffect, a low angle 58 is highly responsive in transmission ratio changebut potentially more difficult to control or stabilize, while a highangle can be less responsive in transmission ratio change but easy tocontrol by comparison. In some embodiments, where it is desirable tohave high speed, fast shift rates, the angle 58 can be, for example, 10degrees. In other embodiments, where it is desirable to have slowerspeed, precise control of transmission ratio, the angle 58 can be about30 degrees. However, the said values of the angle 58 are provided as anillustrative example, and the angle 58 can be varied in any manner adesigner desires. In some embodiments, the angle 58 can be any angle inthe range of 10 to 25 degrees including any angle in between orfractions thereof. For example, the angle can be 10, 11, 12, 13, 14, 15,16, 17, 18, 19, 20, 21, 22, 23, 24, 25, or any portion thereof. In otherembodiments, the angle 58 can be 20 degrees. In one embodiment, theradially off-set guide slots 54 can be arranged so that the constructionline 60 is linearly offset from a construction line 61 by a distance 62.The construction line 61 is parallel to the construction line 60 andintersects the center of the disc-shaped body 50. In other embodiments,such as the one illustrated in FIG. 8A, the second stator 38 can beprovided with a guide slot 53. The guide slot 53 can be substantiallysimilar to the guide slot 54. The guide slot 53 can have a substantiallycurved profile when viewed in the plane of the page of FIG. 8A. Thecurvature of the guide slot 53 can be generally defined by aconstruction line 57. For illustrative purposes, a construction line 57can be shown tangent to the construction line 60. In some embodiments,the construction line 57 is a constant radius curve. In otherembodiments, the construction line 57 can be a non-constant radiuscurve. The curvature of the construction line 57, and consequently thecurvature of the guide slot 53, can be configured to provide the desiredcontrol stability and response of the CVT 10.

Turning now to FIGS. 10-13, in one embodiment the first stator 36 is asubstantially disc-shaped body 70 having a central bore 72. In someembodiments, the central bore 72 can be configured to couple to thestator driver assembly 44. The disc-shaped body 70 can be provided witha plurality of curved guide slots 74 arranged angularly about thecentral bore 72. The guide slots 74 are aligned with a radialconstruction line 76 when viewed in the plane of the page of FIG. 12. Insome embodiments, the first stator 36 can be provided with guide slots74 that are angularly offset in a similar configuration as the guideslots 54. In some embodiments, the first traction ring 28 can carry lesstorque than the traction ring 32 during operation of the CVT 10. It maybe desirable in some applications to place the first stator 36 inproximity to the first traction ring 28 so that the first stator 36operates with lower torque than, for example, the second stator 38.

Referring now to FIGS. 14-16, in one embodiment the timing plate 40 is asubstantially disc-shaped body 80 having a central bore 82. Thedisc-shaped body 80 is provided with a plurality of helical grooves 84formed on a first face. The helical grooves 84 are configured tooperably couple to the planet axles 42. In one embodiment, the helicalgrooves 84 are angled with respect to the guide slots 74. In someembodiments, the angle of the helical grooves 84 with respect to theguide slots 74 is about 40 degrees when viewed down the longitudinalaxis of the CVT 10. In one embodiment, the timing plate is provided withtabs 86. The tabs 86 facilitate the coupling of the timing plate 40 to,for example, the stator driver assembly 44. In some embodiments, thetiming plate 40 is adapted to be rotationally unconstrained to thestator driver assembly 44.

Passing now to FIGS. 17 and 18 and referring again to FIG. 5, in oneembodiment the stator driver assembly 44 includes a compound planetarygear set having a sun gear 90 arranged to couple to the shift tube 18.The stator driver assembly 44 includes a number of planet gears 92coupled to first and second ring gears 94, 96. The first ring gear 94can couple to the main shaft 22 while the second ring gear 96 can coupleto the first stator 36. In one embodiment, the stator driver assembly 44includes a carrier 98 (FIG. 5). The carrier 98 can couple to the timingplate 40. The carrier 98 can couple to the planetary gears 92. Thenumber of teeth and pitch of the sun gear 90, the planet gears 92, andthe first and second ring gears 94, 96 can be sized to provide thedesired rotation of the first stator 36. In one embodiment, thereduction provided by the stator driver assembly 44 is in the range ofabout 0.019 rotations of the ring gear 96 to one rotation of the sungear 90. In some embodiments, the ration of the carrier 98 is about 0.68rotations to one rotation of the sun gear 90. There are many ratiocombinations that are possible with the stator driver assembly 44.

Turning now to FIGS. 19 and 20, in one embodiment a stator driverassembly 100 can include a compound planocentric gear set having a fixedring 102, an output ring 104, and a compound orbital planet gear 106.The compound orbital planet gear 106 can be coupled to an eccentricdriver 108. The eccentric driver 108 can be provided with an eccentriclobe surface 109 that is configured to engage an inner bore 110 of thecompound orbital planet gear 106. In one embodiment, the eccentricdriver 108 can be rotated by the shift tube 18, for example. In someembodiments, the compound orbital planet gear 106 is provided with afirst gear 112 and a second gear 114. The first gear 112 couples to thefixed ring 102. The second gear 114 couples to the output ring 104. Inone embodiment, the stator driver assembly 100 can be configured toprovide a ratio of 0.01 to 0.05 turns of the orbital planet gear 106 toabout one turn of the eccentric driver 108. In some embodiments, theratio range is such that a positive rotation of the eccentric driver 108can result in either a clockwise or a counterclockwise rotation of theoutput ring gear 104. The ratio range can be 0.01 to 0.05 turns of theoutput ring gear 104 to one turn of the eccentric driver 108.

Referring now to FIGS. 21 and 22, in one embodiment a stator driverassembly 120 can include a planocentric gear set 120 having a fixedcarrier 122 coupled to first and second orbital planet gears 124, 126.The first and second orbital planet gears 124, 126 couple to an outputring 128. The first and second orbital planet gears 124, 126 can becoupled to an eccentric driver 130. In one embodiment, the eccentricdriver 130 can be coupled to the shift tube 18, for example. In someembodiments, the eccentric driver 130 is provided with eccentric lobesurfaces 131A, 131B that are configured to engage first and second innerbores 132A, 132B of the first and second orbital planet gears 124, 126,respectively. The fixed carrier 122 can be provided with a number ofpins 134 to facilitate the coupling of the fixed carrier 122 to a numberof holes 136A, 136B of the first and second orbital planet gears 124,126, respectively. Typically, the holes 136A, 136B have a largerdiameter than the pins 134 to provide a small degree of freedom to thefirst and second orbital planet gears 124, 126. The degree of freedomallows the first and second orbital gears 124, 126 to orbit about thelongitudinal axis while substantially preventing rotation of the firstand second orbital planet gears 124, 126 about the longitudinal axis.The first and second orbital planet gears 124, 126 share the torquetransfer to the output ring 128. The eccentric lobe surfaces 131 can beconfigured to prevent backlash between the first and second orbitalplanet gears 124, 126. In one embodiment, the ratio range of the statordriver assembly 120 is about 0.03 rotations of the output ring 128 toone rotation of the eccentric driver 130.

Passing now to FIGS. 23 and 24, in one embodiment a CVT 140 can includea number of traction planet assemblies 142, for example six tractionplanet assemblies 142, arranged angularly about a main axle 144. Themain axle 144 generally defines a longitudinal axis of the CVT 140. Thetraction planet assemblies 142 are in contact with a traction sunassembly 146. The traction sun assembly 146 is located radially inwardof the traction planet assemblies 142. The traction sun assembly 146 iscoaxial with, the main axle 144. The CVT 140 includes first and secondtraction rings 148, 150, in contact with each of the traction planetassemblies 142. In one embodiment, the first traction ring 148 iscoupled to a first axial force generator assembly 152. The first axialforce generator assembly 152 is coupled to an input driver ring 154. Theinput driver ring 154 is configured to receive an input power. Thesecond traction ring 150 is coupled to a second axial force generatorassembly 156. In one embodiment, the second axial force generator 156 isconfigured to transfer a power out of the CVT 140.

Still referring to FIGS. 23 and 24, in one embodiment the CVT 140includes a first stator 160 coupled to a reaction plate 162. The CVT 140includes a second stator 164 operably coupled to the first stator 160.The first and second stators 160, 164 and the reaction plate 162 arecoaxial with the main axle 144. In one embodiment, the first stator 160and the reaction plate 162 are substantially non-rotatable about themain axle 144. The second stator 164 can be configured to rotate aboutthe main axle 144 relative to the first stator 160. The first stator 160can be provided with a number of guide slots 161. The guide slots 161can be arranged on the first stator 160 in a substantially similarmanner as the curved guide slots 74 (FIG. 12) are arranged on the stator36. The second stator 164 can be provided with a number of guide slots165. The guide slots 165 can be arranged substantially similar to thecurved guide slots 54 (FIG. 8) on the stator 38. Each of the tractionplanet assemblies 142 couples to the guide slots 161 and 165. In oneembodiment, the traction planet assemblies 142 are provided with aplanet axle support 143. The planet axle supports 143 have a top-hatcross-section when viewed in the plane of the page of FIG. 23. In someembodiments, the planet axle supports 143 can be formed as an integralcomponent as shown in FIG. 23. In other embodiments, the planet axlesupports 143 can be divided into two components: a cap 143A and a ring143B, where the ring 143B is coupled to the reaction plate 162 and thecap 143A is coupled to the second stator 164, for example. In someembodiments, the ring 143B can be an o-ring (not shown), in which casethe planet axle is adapted to receive the o-ring. During operation ofthe CVT 140, a rotation of the second stator 164 with respect to thefirst stator 160 induces a skew condition on the traction planetassemblies 142 to thereby facilitate a change in the speed ratio of theCVT 140. The first and second stators 160, 164 are coupled to each ofthe traction planet assemblies 142.

Referring now to FIGS. 25-27B, in some embodiments, the CVT 140 includesa stator driver 166 coaxial with, and rotatable about the main axle 144.The stator driver 166 can be configured to operably couple to, forexample, a cable actuator via a pulley or some other suitable coupling(not shown) for facilitating a rotation of the stator driver 166 aboutthe main axle 144. In one embodiment, the stator driver 166 couples to aset of eccentric gears 168. The eccentric gear 168 can be provided withgear teeth (not shown) to interface with a gear ring 169 of the statordriver 166. The eccentric gears 168 couple to the second stator 164 andthe reaction plate 162. Each of the eccentric gears 168 has a cam lobe170 extending from a reaction lobe 172. In one embodiment, the cam lobe170 can be surrounded by an anti-friction sleeve or bushing (not shown)to reduce friction between the eccentric gear 168 and the reaction plate162. The cam lobe 170 and the reaction lobe 172 attach to a gear ring174. The rotational center 171 of the cam lobe 170 is offset from therotational center 173 of the reaction lobe 172 by a distance D whenviewed in the plane of FIG. 27B. In one embodiment, the distance D is inthe range of about 0.5 mm to about 5 mm. In some embodiments, thedistance D is about 3.1 mm. In one embodiment, the cam lobes 170 coupleto a number of guide slots 176 provided on the reaction plate 162. Thereaction lobes 172 slidingly couple to a number of guide bores 178provided on the second stator 164. In one embodiment, the CVT 140 canhave one or more gears 168. In some embodiments, the CVT 140 has threeeccentric gears 168.

Referring still to FIGS. 27A and 27B, in one embodiment the first stator160 is provided with a number of fingers 180. Each finger 180 isprovided with a reaction member 182 extending axially from the finger180. The reaction member 182 is configured to couple to the reactionplate 162. In one embodiment, the reaction members 182 can couple to thereaction plate 162 through insertion into a set of holes 184 with, forexample, a press-fit. The reaction members 182 extend axially past thereaction plate 162 and come into contact (under certain operatingconditions of the CVT 140) with a number of shoulders 186 formed on thesecond stator 164. In one embodiment, the reaction member 162 isprovided with a number of clearance slots 187. The clearance slots 187are generally aligned with the guide slots 161 and 165 and are sized toaccommodate the traction planet assemblies 142. In one embodiment, thefirst stator 160 can be provided with a number of splines 189 that areconfigured to engage a number of splines 190 formed on the reactionplate 162.

During operation of the CVT 140, the stator driver 166 can be rotated tothereby rotate the eccentric gears 168. Since the rotational center 171of the cam lobe 170 is offset from the rotational center 173 of thereaction lobe 172, a rotation of the eccentric gears 168 tends to rotatethe second stator 164 with respect to the first stator 160. The offset Dprovides a moment arm that allows a force to be transferred from thesecond stator 164 to the reaction plate 162. Thus, a torque applied tothe second stator 164 during operation of the CVT 140 can be reacted bythe reaction plate 162. Therefore, the amount of torque required torotate the stator driver 166 is low.

Referring now to FIG. 27C, in one embodiment the guide slots 176 of thereaction plate 162 can be configured to couple to a sliding block 206.The sliding block 206 can couple to the cam lobe 170. In one embodiment,the sliding block 206 is made from a low friction material. The slidingblock 206 can have flat sides adapted to slidingly engage the guide slot176. The flat sides facilitate the reduction of pressure on reactionplate 162, which also lowers friction.

Passing now to FIGS. 28 and 29, in one embodiment a shifting mechanism250 can be configured to cooperate with the CVT 10, the CVT 140, or anyother comparable CVT having a skew-based control system. In oneembodiment, the shifting mechanism 250 includes a reaction arm 252coupled to, for example, the main axle 22. The reaction arm 252 issubstantially non-rotatable with respect to the main axle 22. In oneembodiment, the reaction arm 252 is provided with a splined bore 253configured to engage the main axle 22. The shifting mechanism 250 isprovided with a shift arm 254 coupled to, for example, the shift tube18. In one embodiment, the shift arm 254 is provided with a splined bore255 configured to engage the shift tube 18. The shift arm 254 isconfigured to rotate with respect to the reaction arm 252. The shiftingmechanism 250 is configured to couple to a cable 256. The cable 256 canbe of any type well-known in the bicycle industry. The cable 256 can beprovided with a cable end 258. The cable end 258 is substantiallycylindrical. In one embodiment, the cable end 258 is coupled to a guideslot 260 provided on the reaction arm 252. The cable end 258 is coupledto a guide slot 261 provided on the shift arm 254. The cable end 258 isadapted to slide in the guide slots 260, 261. The cable end 258 can becoupled to a spring 262. The spring 262 couples to the reaction arm 252to thereby bias the cable end 258 toward on end of the guide slot 260. Amovement of the cable 256 tends to translate the cable end 258 in theguide slots 260, 261, which thereby rotates the shift arm 254 withrespect to the reaction arm 252. A rotation of the shift arm 254 therebyrotates, for example, the shift tube 18, which tends to shift thetransmission ratio of the CVT 10.

Referring now to FIG. 30, in one embodiment a shifting mechanism 280 canbe configured to cooperate with the CVT 10, the CVT 140, or any othercomparable CVT having a skew-based control system. In one embodiment,the shifting mechanism 280 includes a reaction arm 282 coupled to, forexample, the main axle 22. The reaction arm 282 is substantiallynon-rotatable with respect to the main axle 22. In one embodiment, thereaction arm 282 is provided with a hole 284 to facilitate the couplingof the reaction arm to a standard cable (not shown). The shiftingmechanism 280 is provided with a rocker arm 286. The rocker arm 286 canbe configured to couple to a cable (not shown) to facilitate a rotationof the rocker arm 286 with respect to the reaction arm 282. In oneembodiment, the rocker arm 286 is provided with a D-shaped pivot 288that is adapted to transfer a torque from the rocker arm 286 to a shifttube driver (not shown). In one embodiment, the shift tube driver can bea gear adapted to couple to, for example, the shift tube 18. In someembodiments, the shift tube driver can be a pulley adapted to couple tothe shift tube 18. In other embodiments, the shift tube driver can be abelt, or other suitable coupling, adapted to transfer a torque from therocker arm 286 to the shift tube 18.

Turning now to FIG. 31, in one embodiment a shifting mechanism 290 canbe configured to cooperate with the CVT 10, the CVT 140, or any othercomparable CVT having a skew-based control system. The shiftingmechanism 290 can be provided with an input gear 292 adapted to coupleto a standard cable (not shown) via, for example, a pulley or some othersuitable coupling. The shifting mechanism 290 is provided with atransfer gear 294 coupled to the input gear 292. The input gear 292 isprovided with a bore 296. The transfer gear 294 is provided with a bore298. The bores 296, 298 are adapted to attach to a fixed member such asa bicycle frame or a reaction arm such as the reaction arm 282 (notshown in FIG. 29). The transfer gear 294 is provided with an eccentricguide bore 300. The shifting mechanism 290 is provided with a shift arm302 operably coupled to the eccentric guide bore 300 via, for example, adowel (not shown). In one embodiment, the shift arm 302 couples to, forexample, the shift tube 18. A shift in a transmission ratio duringoperation of, for example, the CVT 10, can be achieved by rotating theinput gear 292 to thereby rotate the transfer gear 294 about the bore298. A rotation of the transfer gear 294 tends to rotate the shift arm302 via the eccentric guide bore 300.

Referring now to FIGS. 32 and 33, in one embodiment a shifting mechanism310 can include a substantially non-rotatable reaction arm 311. Theshifting mechanism 310 is provided with a pulley 312 coupled to, forexample, a shift tube 18 via a splined bore 313. The pulley 312 isprovided with a cable end attachment interface 314. In some embodiments,the pulley 312 can have an eccentric shape. In other embodiments, thepulley 312 can be a circular shape. In yet other embodiments, the shapeof the pulley 312 is configured to provide a desired ratio betweenrotations of the shift tube 18 and the resulting transmission ratio ofthe CVT 10. The reaction arm 311 is provided with a cable housinginterface 315 that is configured to cooperate with a standard cable andcable housing (not shown). The reaction arm 311 is provided with asplined bore 316. In one embodiment, the shifting mechanism 310 isprovided with an indexing washer 317 that is configured to couple to thesplined bore 316. The indexing washer 317 has a number of indexingmarkings 318. The indexing washer 317 can have an inner bore 319configured to mate with, for example, the main axle 22, in such a way asto prevent rotation of the indexing washer 317, and consequently thereaction arm 311, with respect to the main axle 22. In one embodiment,the indexing washer 317 can be provided with a slot formed on the innerbore. The slot can receive a frictional spring type element (not shown)that can be made of wire or plastic to employ a slight interference orfrictional fit onto the main axle 22. The indexing washer 317 can aid inthe retention of the reaction arm 311 onto the main shaft 22 such thatit will not accidentally fall off while trying to fit the CVT 10 into abike frame. The shifting mechanism 310 provides advantages for removalof a wheel (not shown) equipped with the CVT 10, for example, from abicycle as a complete assembly without any tools, thus allowingdisconnection between the cable that is attached to the bike frame andthe CVT 10. Once an orientation between the bike frame dropout slots andthe directional requirement for the cable location on the bike frame isestablished, the indexing markings 318 can be used to maintain theorientation upon removal and re-installation of the wheel.

Turning now to FIG. 34, in one embodiment a shifting mechanism 320 caninclude a reaction arm 322 coupled to, for example, a bicycle frame 324.The shifting mechanism 320 is provided with a shift arm 326. In oneembodiment, the shift arm 326 can be coupled to, for example, the shifttube 18. The shift arm 326 is coupled to a first lever 328 at a firstpivot 330. The first lever 328 is coupled to a second lever 332 at asecond pivot 334. The second lever 332 is coupled to the reaction arm322 at a third pivot 336. In one embodiment, the shifting mechanism 320is provided with a spring 338 coupled to the second pivot 334 and thereaction arm 322. In some embodiments, the first, second, and thirdpivots 330, 334, 336 are common fasteners configured to provide relativerotation between the first and second levers 328, 332. In oneembodiment, the shifting mechanism 320 can be coupled to a standardcable (not shown) at the pivot 334. The standard cable can be configuredto translate the pivot 334 in the rightward and leftward direction (inreference to plane of FIG. 34). The translation of the pivot 334 tendsto rotate the shift arm 326.

Passing now FIG. 35, in one embodiment a shifting mechanism 350 can beprovided with a reaction arm 352 coupled to, for example, a bicycleframe 354. The reaction arm 352 can be adapted to couple to a cable 355and a cable sleeve 356. In one embodiment, the shifting mechanism 350has a shift arm 358 coupled to, for example, the shift tube 18. Theshifting mechanism 350 has a lever 360 coupled to the shift arm 358 at afirst pivot 362. The lever 360 is coupled to the cable 355 at a secondpivot 364. The second pivot 364 is located on one end of the lever 360at a distal location from the first pivot 362. In one embodiment, theshifting mechanism 350 is provided with a linkage 366 coupled to thereaction arm 352 at a pivot 368. The linkage 366 is coupled to the lever360 at a pivot 370. The pivot 370 is located between the first andsecond pivots 362, 364. The cable 355 can be pulled to thereby move thelever 360. The lever 360 tends to rotate about the pivot 370 tofacilitate a rotation of the shift arm 358.

Turning now to FIGS. 36-37B, in one embodiment a shifting mechanism 400can couple to a handle grip 402 via a cable 404. The shifting mechanism400 includes a pulley 406. The pulley 406 can have a splined inner boreadapted to couple to a reaction member 408. In one embodiment, thepulley 406 can operably couple to the shift tube 18, for example. Thereaction member 408 can be provided with a pocket 410. The pocket 410 isadapted to support a spring 412. In one embodiment, the spring 412 iscoupled to a roller 414. The spring 412 tends to press the roller 414towards the splined inner bore of the pulley 406. The roller 414 appliesa holding force on the pulley 406 which facilitates the engagement ofthe splined inner bore of the pulley 406 to the splined circumference ofthe reaction member 408 at, for example, a location 416. In oneembodiment, the shifting mechanism 400 is positioned in proximity to theCVT 10, for example. In some embodiments, the shifting mechanism 400 canbe located within, or in proximity to, the handle grip 402.

During operation of the CVT 10, for example, a control force is appliedto the cable 404 to facilitate a rotation of the pulley 406. The controlforce induces a tension in the cable 404, which tends to displace thepulley 406 in the direction of the control force, for example the pulley406 displaces in a rightward direction when viewed in the plane of thepage of FIG. 37A. For illustrative purposes, FIG. 37B depicts a positionof the pulley 406 in the presence of cable tension in comparison to anon-tensioned position 406′ (depicted in dashed lines). The pulley 406and the reaction member 408 do not contact at the location 416 in thepresence of cable tension which enables the pulley 406 to rotaterelative to the reaction member 408. Once the control force is removedfrom the cable 404 and tension is relieved, the spring 412 urges thepulley 406 in the leftward direction (in reference to FIG. 40A), whichengages the pulley 406 and the reaction member 408 at the location 416.

Passing now to FIGS. 38 and 39, in one embodiment a CVT 450 can besubstantially similar to the CVT 10. For description purposes, only thedifferences between the CVT 450 and the CVT 10 will be discussed. TheCVT 450 has a plurality of traction planet assemblies 452 coupled to afirst stator 454 and a second stator 456. The traction planet assemblies452 are configured to contact an idler assembly 458. In one embodiment,the second stator 456 is coupled to a shifting mechanism 460. Theshifting mechanism 460 includes a roller 462 in contact with the secondstator 456 and a guide member 464. The guide member 464 can beconfigured to rotate about a main axle 465. In one embodiment, the guidemember 464 is coupled to a shift tube 466. The shift tube 466 can besubstantially similar to the shift tube 18. The shifting mechanism 460can include a reaction arm 468 in contact with the roller 462. Thereaction arm 468 can rotate about a pivot 467. The pivot 467 can becoupled to a grounded arm 469. The grounded arm 469 can attach to themain axle 465. In one embodiment, the reaction arm 468 couples to thefirst stator 454 at an end 470. The end 470 can be pinned to the firststator 454 through a suitable coupling means. In some embodiments, thecoupling between the first stator 454 and the end 470 involves a rod(not shown) arranged between the traction planet assemblies 452. The rodcan be positioned axially to facilitate the coupling of the first stator454 to the end 470. The reaction arm 468 can be provided with at leastone surface 471 adapted to radially guide the roller 462. Duringoperation of the CVT 450, the second stator 456 reacts torque from thetraction planet assemblies 452. The torque can be transferred from thesecond stator 456 via the roller 462 to the surface 471 of the reactionarm 468. A relative rotation between the first and second stators 454,456 can be facilitated by a rotation of the guide member 464 with, forexample, a shift arm 472. The shift arm 472 can be substantially similarto the shift arm 254, the shift arm 302, the shift arm 326, or any othersuitable shift arm.

Referring again to FIG. 38, in one embodiment the assembly 458 caninclude a first rolling element 480 and a second rolling element 481,both in contact with each of the traction planet assemblies 452. Thefirst and second rolling elements 480, 481 are supported with bearings482, 483 on a support tube 484. In one embodiment, the support tube 484is substantially fixed from axial movement. In some embodiments, thebearings 482, 483 are directly coupled to the main axle 22. In otherembodiments, the idler assembly 458 can float with respect to the mainaxle 22.

Turning now to FIG. 40, in one embodiment a shifting mechanism 550 caninclude a stator 552 that is substantially similar to the stator 38. Theshifting mechanism 550 is provided with a shift tube 554 that can besubstantially similar to the shift tube 18. The shift tube 554 isarranged coaxial with the stator 552. In one embodiment, the shift tube554 can be configured to couple to a push link 556. An interface 555between the shift tube 554 and the push link 556 can be a pinned jointor other suitable coupling. The shifting mechanism 550 can be providedwith a reaction arm 558 that is adapted to be substantiallynon-rotatable. The reaction arm 558 is coupled to the stator 552 via aspring 560. The shifting mechanism 550 is provided with a linkage 562coupled to the push link 556 on a first end and coupled to the reactionarm 558 on a second end. Each end of the linkage 562 is configured topivot. The shifting mechanism 550 can be provided with a linkage 564coupled at a first end to the push link 556 and coupled at a second endto the stator 552. Each end of the linkage 564 is configured to pivot.

During operation, the stator 552 can be rotated to facilitate a changein a transmission ratio. The shift tube 554 can be rotated by a standardcable (not shown), which tends to move the push link 556. The movementof the push link 556 tends to displace the linkage 564 with respect tothe linkage 562 in a scissor-like motion to thereby rotate the stator552. A rotation of the stator 552 can also be facilitated by a change ina torque applied to the stator 552 during operation of a CVT. Forexample, the spring 560 couples the reaction arm 558 to the stator 552,therefore a change in torque applied to the stator 552 results in adisplacement of the spring 560. A change in the displacement of thespring 560 corresponds to a rotation of the stator 552. Consequently, adesired operating torque for a CVT can be prescribed for a desired speedratio by appropriately sizing and preloading the spring 560.

Passing now to FIG. 41, in one embodiment a shifting mechanism 600 caninclude a stator 602 that is substantially similar to the stator 38. Theshifting mechanism 600 can include a driver 604 adapted to cooperatewith, for example, a pulley (not shown) or other suitable actuator. Thedriver 604 can be provided with gear teeth to engage a driven gear 606.The driven gear 606 has a slot 608 that is adapted to engage a pin 610.The pin 610 is attached to the stator 602. A rotation of the driver 604tends to rotate the driven gear 606. The rotation of the driven gear 606urges the pin 610 to rotate the stator 602. Consequently, the pin 610slides in the slot 608.

Referring now to FIGS. 42 and 43, in one embodiment a CVT 620 can beprovided with a shifting mechanism 621. The CVT 620 can be substantiallysimilar to the CVT 10. For description purposes, only the differencesbetween the CVT 620 and the CVT 10 will be discussed. The shiftingmechanism 621 can have a shift tube 622 configured to carry a number ofrollers 624. The shift tube 622 is adapted to translate axially. Therollers 624 engage a first helical groove 626 formed in a main shaft628. The rollers 624 engage a second helical groove 630 formed in afirst stator 632. In one embodiment, the first and second helicalgrooves 626, 630 are high lead. In some embodiments, the first andsecond helical grooves 626, 630 can be nearly axial grooves. The firststator 632 can be substantially similar to the stator 38. An axialtranslation of the shift tube 622 tends to move the rollers 624 in thehelical grooves to thereby rotate the first stator 632 with respect to asecond stator 634. In one embodiment, the first and second helicalgrooves 626, 630 have different leads so that at least a portion of thetorque applied to the first stator 632 can be transferred to the mainshaft 628 during operation of the CVT 620. In one embodiment, the mainshaft 628 and the first and second stators 632, 634 are adapted toreceive a power input and rotate about a longitudinal axis 636. In someembodiments, the shift tube 622 can be suitably coupled to an actuator(not shown) to facilitate the axial translation of the shift tube 622along the main shaft 628.

Turning now to FIG. 44, in one embodiment the CVT 620 can be providedwith a shift tube 640. The shift tube 640 can have a slot 642 adapted tocouple to the rollers 624. The shift tube 640 can be configured torotate about the main shaft 628. In one embodiment, the shift tube 640can be coupled to a suitable actuator to facilitate a rotation of theshift tube 640. The rotation of the shift tube 640 tends to rotate theroller 624 to thereby facilitate a relative rotation between stators634, 632.

Passing now to FIG. 45, in one embodiment a CVT 660 includes, amongother things, first and second traction rings 661, 662 and an idler 663in contact with a group of traction planet assemblies 664. The CVT 660can be substantially similar to the CVT 10. For description purposes,only the differences between the CVT 660 and the CVT 10 will bediscussed. The CVT 660 can be provided with a first stator 666 and asecond stator 668 operably coupled to the traction planet assemblies664. The first and second stators 666, 668 can be configuredsubstantially similar to the stators 36, 38. In one embodiment, the CVT660 can be provided with a well-known fly-ball governor. For descriptionpurposes, the fly-ball governor is depicted as a ball 670. In someembodiments, the fly-ball governor can include a spring adjustment andappropriate bearings (not shown). The fly-ball governor can include theball 670 in contact with a stator driver 672 and a stator member 674. Inone embodiment, the stators 666, 668 are adapted to receive an inputpower and rotate about the longitudinal axis LA. The ball 670 tends toradially displace proportional to the speed of the first and secondstators 666, 668. A radial displacement of the ball 670 can correspondto an axial translation of the stator driver 672. The stator driver 672can have a threaded interface with the second stator 668. An axialtranslation of the stator driver 672 facilitates a rotation of thesecond stator 668 with respect to the first stator 666. In analternative embodiment, the fly-ball governor is configured to cooperatewith the first traction ring 661 so that a change in the speed of thefirst traction ring 661 tends to rotate the first stator 666 withrespect to the second stator 668. In some embodiments, the firsttraction ring 661 can be configured to receive an input power, and thesecond traction ring 662 can be configured to transfer an output powerout of the CVT 660.

Referring now to FIGS. 46A and 46B, in one embodiment a CVT 700includes, among other things, first and second traction rings 701, 702and an idler 703 in contact with a group of traction planet assemblies704. The traction planet assemblies 704 can be operably coupled to firstand second stators 706, 708. In one embodiment, the first stator 706 canbe coupled to a fly-ball governor 710. The fly-ball governor 710 can beconfigured to rotate the first stator 706 corresponding to a change inthe rotational speed. The second stator 708 can be coupled to a springmember 712. In some embodiments, the first and second stators 706, 708can be adapted to receive an input power. In one embodiment, the firsttraction ring 701 can be adapted to receive an input power. In otherembodiments, a CVT 720 can be configured to include a fly-ball governor722 coupled to a first traction ring 721 and a first stator 723. Thefirst traction ring 721 and the first stator 723 can be substantiallysimilar to the first traction ring 701 and the first stator 706,respectively. During operation of the CVT 700 or the CVT 720, the spring712 can react a torque transferred from the second stator 708. Thespring 712 can displace relative to the magnitude of the torque. Thesecond stator 708 tends to rotate with respect to the first stator 706corresponding to the displacement of the spring 712. Therefore, adesired operating torque for a CVT can be prescribed by appropriatelysizing and preloading the spring 712. The combination of the fly-ballgovernor 710 or 722 with the spring 712 provides both speed control andtorque control for the CVT 700 or 720, which is desirable in mobileground vehicles, for example.

Passing now to FIG. 47, in one embodiment a control system 750 can beconfigured to cooperate with, for example, CVT 10 or any of the CVTembodiments disclosed here. The control system 750 can include a pump752 in fluid communication with a flow control valve 754. The flowcontrol valve 754 can have a coupling 756 adapted to rotate, forexample, a stator 758. The flow control valve 754 can be in fluidcommunication with an orifice 760. The orifice 760 directs a fluid to afluid reservoir 762. The fluid reservoir 762 can supply the fluid to thepump 752. In one embodiment, the orifice 760 is a fixed orifice. In someembodiments, the orifice 760 is a variable orifice. During operation, atransmission ratio can be adjusted and maintained using the flow controlvalve 754. A torque applied to the stator 758 can be reacted by the flowcontrol valve 754 via the coupling 756. In alternative embodiments, thecontrol system 750 can be configured to function as a torque limiter forthe CVT 10 or any similar CVT having a skew-based control system.

Turning now to FIG. 48, in one embodiment a bicycle 800 can include theCVT 10, for example, coupled to a wheel 801 with spokes 802. The CVT 10can be provided with a shift arm 804 that is adapted to operably coupleto, for example, a shift tube 18. The bicycle 800 can include a drivechain 806 coupled to a well-known chain tensioner 808. The chaintensioner 808 can be coupled to the shift arm 804 via a turn buckle 810,for example. During operation of the bicycle 800, a user applies a forceto the pedals 812 resulting in an oscillatory torque transmission to thechain 806. The oscillatory torque tends to tension and un-tension thechain 806, which causes the chain 806 to displace and move the chaintensioner 808. The movement of the chain tension 808 tends to rotate theshift arm 804.

Passing now to FIGS. 49 and 50, in one embodiment a CVT 900 can have anumber of traction planet assemblies 902 arranged radially about a mainaxle 904. The CVT 900 can be substantially similar to the CVT 140. Fordescription purposes, only the differences between the CVT 900 and theCVT 140 will be discussed. In one embodiment, the CVT 900 is adapted toreceive an input power with, for example, a pulley 906 or other suitablecoupling. The pulley 906 can be coupled to the main axle 904. The CVT900 can have an output gear 905 configured to transfer power from atraction ring 907. The traction ring 907 can be in contact with each ofthe traction planet assemblies 902. In one embodiment, the main axle 904is coupled to a first stator 908 and a second stator 910. The first andsecond stators 908, 910 can be configured to support each of thetraction planet assemblies 902. In one embodiment, the first and secondstators 908, 910 are adapted to transfer the input power to the tractionplanet assemblies 902. The first and second stators 908, 910 areconfigured to rotate with the main axle 904. The first and secondstators 908, 910 are adapted to rotate with respect to each other toinduce a skew condition on the traction planet assemblies 902. The skewcondition facilitates a change in transmission ratio of the CVT 900.

In one embodiment, the CVT 900 has a number of eccentric gears 912coupled to the first stator 908. The eccentric gears 912 can besubstantially similar to the eccentric gears 168. The eccentric gears912 couple to a shift tube 914. The shift tube 914 can couple to acompound planetary gear set having a first ring gear 916 and a secondring gear 917, each ring gear 916, 917 coupled to a number of planetgears 918. The planet gears 918A, 918B share a common axle and are freeto rotate with respect to each other. The shift tube 914 can couple to afirst sun gear 920. In one embodiment, a second sun gear 922 can coupleto the main axle 904. The first ring gear 916 is coupled to, forexample, a non-rotatable housing (not shown). The second ring gear 917can be coupled to a suitable actuator such as a motor (not shown).During operation of the CVT 900, a relative rotation between the firstring gear 916 and the second ring gear 917 tends to facilitate arelative rotation between the first stator 908 and the second stator910.

Turning now to FIGS. 51 and 52, in one embodiment a CVT 1000 can besubstantially similar to the CVT 900. For description purposes, only thedifferences between the CVT 1000 and the CVT 900 will be discussed. TheCVT 1000 is configured to receive an input power from, for example, thepulley 906. The pulley 906 can be coupled to a main shaft 1002. In oneembodiment, the first traction ring 907 is substantially non-rotatableabout the main shaft 1002. The CVT 1000 can have an output gear 1004configured to receive power from a second traction ring 1006. The outputgear 1004 is coaxial with a shift tube 1008. The shift tube 1008 iscoupled to the first stator 908. In one embodiment, the shift tube 1008is coupled to the first sun gear 920. In some embodiments, the CVT 1000can have a spring 1010 coupled to the first stator 908. During operationof the CVT 1000, a change in the transmission ratio is facilitated by arelative rotation between the first and second stators 908, 910. Thefirst stator 908 can be rotated with respect to the second stator 910via a rotation of the shift tube 1008. The shift tube 1008 is rotatedduring operation in a substantially similar manner as the shift tube 914via the sun gear 920.

Passing now to FIG. 53, in one embodiment a CVT 1050 can besubstantially similar to the CVT 1000. For description purposes, onlythe differences between the CVT 1000 and the CVT 1050 will be described.In one embodiment, the CVT 1050 includes a planetary gear set 1052coupled to a first stator 1054 with, for example, a chain or a belt1056. The planetary gear set 1052 can couple to a second stator 1058with, for example, a chain or a belt 1060. The planetary gear set 1052includes a first ring gear 1062 coupled to a number of planet gears1064. The planet gears 1064 couple to a first sun gear 1066. In oneembodiment, the first sun gear 1066 is substantially non-rotatable. Theplanetary gear set 1052 includes a second ring gear 1068 coupled to anumber of planet gears 1070. The planet gears 1070 couple to a secondsun gear 1072. The second sun gear 1072 can be coupled to a suitableactuator (not shown). The actuator can be adapted to rotate the secondsun gear 1072 during operation of the CVT 1050. The planet gears 1064and 1070 can be coupled to a carrier 1074. The carrier 1074 can beadapted to receive an input power 1076 (depicted as an arrow in FIG.53).

Referring now to FIG. 54, in one embodiment a CVT 1100 can besubstantially similar to the CVT 1000. For description purposes, onlythe differences between the CVT 1000 and the CVT 1100 will be described.In one embodiment, the CVT 1100 includes a first stator 1102 and asecond stator 1104. The first stator 1102 can be coupled to an inputshaft 1106 with a chain or belt 1108. The input shaft 1106 is adapted toreceive an input power 1110 (depicted as an arrow in FIG. 54). In oneembodiment, the second stator 1104 is configured to couple to a shifttube 1112 with a chain or a belt 1114. The shift tube 1112 is coupled toa shift tube driver 1116. The shift tube driver 1116 mates to the shifttube 1112 through a set of helical splines 1118. In one embodiment, thehelical splines 1118 are high lead. The shift tube driver 1116 mates tothe input shaft 1106 with a set of straight splines 1120. The shift tubedriver 1116 can be configured to rotate and translate during operationof the CVT 1100. In one embodiment, the shift tube driver 1116 isconfigured to couple to an actuator shaft 1122. The actuator shaft 1122can be substantially non-rotatable. The actuator shaft 1122 can beconfigured to linearly translate. The actuator shaft 1122 is supportedon the shift tube driver 1116 with a number of bearings 1124.

Passing now to FIGS. 55-58, in one embodiment a CVT 1200 can besubstantially similar to the CVT 1000. For description purposes, onlythe differences between the CVT 1000 and the CVT 1200 will be described.In one embodiment, the CVT 1200 is provided with a freewheel driver 1202coupled to the sprocket 14. The sprocket 14 can be attached to thefreewheel driver 1202 with a retaining nut 1204. The freewheel driver1202 can be supported by a first bearing 1206 and a second bearing 1208.In one embodiment, the first bearing 1206 can be a needle rollerbearing, for example. In some embodiments, the second bearing 1208 canbe a ball bearing, for example. The first and second bearings 1206, 1208can be adapted to couple to, for example, the stator driver 166. In oneembodiment, the freewheel driver 1202 is adapted to cooperate with anumber of pawls 1210. The pawls 1210 are coupled to a spring 1212. Inone embodiment, the spring 1212 can be a torsion spring adapted tocouple to each of the pawls 1210. In some embodiments, each of the pawls1210 can be coupled to a spring element 1213 (FIG. 58). The springelements 1213 can be retained in the freewheel driver 1202. The pawls1210 are configured to selectively engage a torque driver 1214. Thetorque driver 1214 can have a number of teeth 1215 (FIG. 57). The teeth1215 are configured to engage the pawls 1210. The torque driver 1214 canbe operably coupled to the input driver ring 154, for example. In someembodiments, the CVT 1200 can be provided with a first dust cover 1216positioned between the freewheel driver 1202 and, for example, a shiftactuator pulley 1218. In some embodiments, the CVT 1200 can be providedwith a second dust cover 1220 positioned between the sprocket 14 and thehub shell 11, for example.

During operation of the CVT 1200, an input torque is transmitted fromthe sprocket 14 to the freewheel driver 1202. The freewheel driver 1202transmits torque in a first rotational direction to the torque driver1214 via the pawls 1210. Under certain operating conditions, the torquedriver 1214 can receive a torque from the driver ring 154 in a secondrotational direction, which tends to disengage the pawls 1210 from thetorque driver 1214 and prevents the transfer of the said torque to thefreewheel driver 1202.

Turning now to FIG. 59, in one embodiment a control system 1250 can beconfigured to cooperate with, for example, the CVT 10 or any of the CVTembodiments disclosed here. The control system 1250 can include a pump1252 in fluid communication with a flow control valve 1254. The flowcontrol valve 1254 can have a coupling 1253 adapted to rotate, forexample, a stator 1255. The flow control valve 1254 can be in fluidcommunication with an orifice 1256. The orifice 1256 directs a fluid toa fluid reservoir 1257. In one embodiment, the flow control valve 1254can be configured to cooperate with a pressure control valve 1258.During operation of the control system 1250, the pressure control valve1258 controls the operating pressure of the flow control valve 1254. Anadjustment of the pressure control valve 1258 or the flow control valve1254 tends to move the coupling 1253 thereby rotating the stator 1255 tofacilitate a change in transmission ratio.

Referring now to FIG. 60, in one embodiment a control system 1280 can beconfigured to cooperate with, for example, the CVT 10 or any of the CVTembodiments disclosed here. The control system 1280 can include a pump1282 in fluid communication with a first pressure control valve 1284 anda second pressure control valve 1286. In one embodiment, the first andsecond pressure control valves 1284, 1286 can be in fluid communicationwith first and second pressure chambers 1288, 1290, respectively. Thefirst and second pressure chambers 1288, 1290 are configured to act onfirst and second pistons 1292, 1294, respectively. The first and secondpistons 1292, 1294 are coupled to, for example, a stator 1296. Duringoperation of the control system 1280, fluid pressure in the pressurechambers 1288, 1290 can displace the pistons 1292, 1294 which tends torotate the stator 1296 to facilitate a change in transmission ratio ofthe CVT 10, for example.

Passing now to FIG. 61, in one embodiment a control system 1300 can beconfigured to cooperate with, for example, the CVT 10 or any of the CVTembodiments disclosed here. The control system 1300 can include a pump1302 in fluid communication with a pressure control valve 1304. The pump1302 can be in fluid communication with a directional control valve1306. In one embodiment, the directional control valve 1306 is in fluidcommunication with first and second pressure chambers 1308, 1310. Insome embodiments, the directional control valve 1306 is a servocontrolled four way directional control valve. The first and secondpressure chambers 1308, 1310 are configured to act on first and secondpistons 1312, 1314, respectively. The first and second pistons 1312,1314 are coupled to, for example, a stator 1316. During operation of thecontrol system 1300, fluid pressure in the pressure chambers 1308, 1310can displace the pistons 1312, 1314 which tends to rotate the stator1316 to facilitate a change in transmission ratio of the CVT 10, forexample. In some embodiments, the displacement of the pistons 1312, 1314can be achieved by control of a position of the valve spool of thedirection control valve 1306.

Referring now to FIGS. 62-65, in one embodiment a shifting mechanism1350 can be coupled to the shift tube 18 of the CVT 10, for example. Theshifting mechanism 1350 is provided with a generally non-rotatablehousing 1352 having a splined bore 1353. The splined bore 1353 can beadapted to operably couple to the main axle 22, for example. Theshifting mechanism 1350 is provided with a pulley 1354 that is rotatablydisposed about the main axle 22. The pulley 1354 has a splined innerbore 1356. In one embodiment, the pulley 1354 is coupled to a number ofplanet gears 1358. The planet gears 1358 are arranged radially about themain axle 22. The planet gears 1358 couple to a cage 1360. The cage 1360has a splined inner bore 1362 that is adapted to couple to a statordriver 1361. The stator driver 1361 can be substantially similar to thestator driver 166, for example. The cage 1360 has a number of planetpockets 1363 that are configured to receive the planet gears 1358. Theplant pockets 1363 can be generally circular cut outs formed on theperiphery of the cage 1360.

In one embodiment, the cage 1360 is coupled to the housing 1352 with aclip 1364. The clip 1364 can be formed with a number of tabs 1365 thatare adapted to engage the housing 1352. In one embodiment, the tabs 1365engage a number of slots 1366 formed on the housing 1352. Onceassembled, the cage 1360 can rotate with respect to the housing 1352while maintaining a consistent axial position with respect to the statordriver 1361. In one embodiment, the shifting mechanism 1350 is providedwith an axle nut 1368. The axle nut 1368 is adapted to couple to themain axle 22. In one embodiment, the shifting mechanism 1350 is providedwith a locking nut 1370 adapted to couple to the splined bore 1356 ofthe housing 1352. The locking nut 1370 is adapted to attach to the axlenut 1368. For example, the axle nut 1368 can be provided with a numberof flat surfaces arranged about the periphery of the body, and thelocking nut 1370 can be provided with a number of mating female surfacesformed about the inner bore of the locking nut 1370. Once assembled, thelocking nut 1370 facilitates the alignment of the housing 1352, andconsequently the shifting mechanism 1350, with respect to the statordriver 1361 and the CVT 10, for example. The housing 1352 has a numberof timing markings 1377 that align upon assembly with a number of indexmarkings 1379 on the locking nut 1370. Once an orientation between thebike frame dropout slots and the directional requirement for the cablelocation on the bike frame is established, the indexing markings 1379can be used to maintain the orientation upon removal and re-installationof the wheel.

Referring still to FIGS. 62-65, in one embodiment the housing 1352 isprovided with a cable housing stop 1372. The cable housing stop 1372extends from the body of the housing 1352 and is configured tofacilitate the alignment and the coupling of a standard bicycle controlcable, for example, with the pulley 1354. The pulley 1354 is providedwith cable end retention tabs 1374. The cable end retention tabs 1374are configured to receive a cable end 1376. The cable end 1376 can beattached to one end of the standard bicycle control cable with a screw,for example.

During operation of the CVT 10, for example, a change in ratio of theCVT 10 can be attained by tensioning a standard bicycle control cable(not shown) to thereby facilitate a rotation of the pulley 1354 withrespect to the housing 1350. The rotation of the pulley 1354 tends torotate the planet gears 1358 about a sun gear 1378. In one embodiment,the sun gear 1378 is formed integral to the housing 1352 (FIG. 65). Therotation of the planet gears 1358 tends to rotate the cage 1360 tothereby rotate the stator driver 1361. It should be noted that thisconfiguration provides a mechanical advantage for transferring torque tothe stator driver 1361 and thereby reduces the effort for shifting theCVT 10.

Turning now to FIG. 66, in one embodiment a traction planet carrierassembly 1400 can be used with any of the CVT embodiments disclosedhere. The traction planet carrier assembly 1400 can include a firststator 1402 adapted to support the traction planets 30, for example. Thefirst stator 1402 couples to a reaction plate 1404. The reaction plate1404 is coaxial with the first stator 1402. The first stator 1402operably couples to a skew stator 1406. The skew stator 1406 is coaxialwith the first stator 1402 and the reaction plate 1404. The skew stator1406 is adapted to rotate with respect to the first stator 1402 and thereaction plate 1404. In one embodiment, the first stator 1402, thereaction plate 1404, and the skew stator 1406 are substantially similarto the first stator 160, the reaction plate 162, and the second stator164, respectively. This first stator 1402 is provided with an inner bore1403 that is adapted to receive, for example, the main axle 144. Thereaction plate 1404 is provided with an inner bore 1405 that is adaptedto receive, for example, the main axle 144. The skew stator 1406 isprovided with an inner bore 1407 that is adapted to receive, forexample, the main axle 144.

Still referring to FIG. 66, in one embodiment the skew stator 1406 isadapted to support a number of eccentric gears 1408. The eccentric gears1408 can be coupled to the stator driver 166, for example. Each of theeccentric gears 1408 includes a pocket 1409 adapted to house to a spring1410. The spring 1410 has a first end 1412 adapted to couple to the skewstator 1406. The spring 1410 has a second end 1414 adapted to couple tothe eccentric gear 1408. During operation of the CVT, a change intransmission ratio can be achieved by rotating the skew stator 1406 withrespect to the first stator 1402. The rotation of the skew stator 1406can be achieved by rotating the eccentric gears 1408. The eccentricgears 1408 couple to the skew stator 1406 in a substantially similar wayas the eccentric gears 148 are coupled to the second stator 164. In oneembodiment, the springs 1410 apply force to the eccentric gears 1408that tend to move the skew stator 1406 to a position corresponding to anunderdrive transmission ratio. In one embodiment, the springs 1410 canbe sized to provide a force capable of overcoming friction forces in theCVT and in the shifting components.

Turning now to FIGS. 67-69, in one embodiment a shifting mechanism 1450can be coupled to the shift tube 18 of the CVT 10, for example. Theshifting mechanism 1450 can be provided with a generally non-rotatablehousing 1452 having a splined inner bore 1453. The splined inner bore1453 is adapted to couple to a locking nut 1454. The locking nut 1454 isprovided with a mating splined circumference 1455. The locking nut 1454is provided with a number of reaction faces 1456 that are configured toengage an axle nut 1457. The axle nut 1457 couples to the main axle 22,for example, with threads. In one embodiment, the shifting mechanism1450 includes a pulley 1458 operably coupled to the housing 1452. Thepulley 1458 is rotatable with respect to the housing 1452. The pulley1458 has a geared inner bore 1459 adapted to couple to a number ofplanet gears 1460. The planet gears 1460 are supported in a cage 1462.The cage 1462 is substantially similar to the cage 1360. The planetgears 1460 couple to a sun gear 1461 formed around the splined innerbore 1453 of the housing 1452. In one embodiment, the cage 1462 has asplined inner bore 1463 that can be coupled to a stator driver such asthe stator driver 1361, for example. The shifting mechanism 1450 caninclude a retainer clip 1464 that couples to the pulley 1458.

Referring again to FIG. 67, in one embodiment the housing 1452 can havea front face 1470 and a back face 1472. Typically, the back face 1472 isarranged in proximity to the hub shell 11, for example, so that thefront face 1470 is in view when the shifting mechanism 1450 is assembledon the CVT 10. The front face 1472 can be provided with a number ofnotches 1474 formed radially about the inner bore 1453. The front face1474 can be provided with a set of recesses 1475 flanking the inner bore1453. The recesses 1475 can be adapted to receive a tool, such as ascrew driver, for removing the locking nut 1454. In one embodiment, thehousing 1452 can be provided with a first cable housing stop 1476arranged between the front face 1470 and the back face 1472. The housing1452 can be provided with a second cable housing stop 1478 arrangedbetween the front face 1470 and the back face 1472. In one embodiment,the first cable housing stop 1476 is generally parallel to the secondcable housing stop 1478. The first and second cable housing stops 1476,1478 are each provided with slots 1480. The slots 1480 facilitate theassembly of a standard bicycle control cable to the housing 1452.

In one embodiment, the pulley 1458 is provided with a tab 1482 extendingfrom the periphery of the pulley 1458. The tab 1482 is adapted to coupleto a cable retainer cap 1484. The tab 1482 can have a first cut-out 1486that is adapted to receive a curved portion 1488 of the cable retainercap 1484. The tab 1482 can be provided with a second cut-out 1490 thatis adapted to receive a cable end stop 1492. The tab 1482 can be formedwith a slot 1487. The slot 1487 facilitates the coupling of the firstand second cables 1496, 1500 to the pulley 1458. The cable retainer cap1484 can be attached to the tab 1482 with a clip 1494. The cableretainer cap 1484 is adapted to receive a first cable 1496. The firstcable 1496 is partially shown in FIGS. 67-70. The first cable 1496 isattached to the cable retainer cap 1484 with a set screw 1497, forexample. The set screw 1497 threads into a hole 1498. The set screw 1497pinches the first cable 1496 against the cable retainer cap 1484 (FIG.70). An end 1496A of the first cable 1496 can extend past the cableretainer cap 1484. Typically the end 1496A is cut closely to the cableretainer cap 1484. In one embodiment, a set screw 1502 is adapted topartially secure a second cable 1500 to the cable retainer cap 1484. Thecable retainer cap 1484 is provided with internal channels for the firstand second cables 1496, 1500. For clarity purposes, only a portion ofthe second cable 1500 is shown in FIGS. 67-69. The first cable 1496 canwrap around the pulley 1458 and exit the shifting mechanism 1450 at thefirst cable housing stop 1476. The second cable 1500 can wrap around thepulley 1458 and exit the shifting mechanism 1450 at the second cablehousing stop 1478.

In one embodiment, the clip 1494 is a generally spring like memberhaving a bend 1504 adapted to couple to a lip 1493 formed on the tab1482. The clip 1494 is provided with a first extension 1506 that extendsfrom the bend 1504 and is configured to generally cover a portion of thecable retainer cap 1484. The clip 1494 is provided with a secondextension 1508 that extends from the bend 1504 and is adapted to providea means for removing or assembling the clip 1494. The clip 1494 can beprovided with a slot 1510 to provided clearance for the second cable1500.

Once assembled, a force can be applied to the first cable 1496 thattends to facilitate a rotation of the pulley 1458 in a first direction,and consequently a change in ratio of the CVT, for example, from anunderdrive ratio towards an overdrive ratio. A force can be applied tothe second cable 1500 that tends to facilitate a rotation of the pulley1458 is a second direction, and consequently a change in ratio of theCVT, for example from an overdrive ratio towards an underdrive ratio.

It should be noted that the description above has provided dimensionsfor certain components or subassemblies. The mentioned dimensions, orranges of dimensions, are provided in order to comply as best aspossible with certain legal requirements, such as best mode. However,the scope of the inventions described herein are to be determined solelyby the language of the claims, and consequently, none of the mentioneddimensions is to be considered limiting on the inventive embodiments,except in so far as any one claim makes a specified dimension, or rangeof thereof, a feature of the claim.

The foregoing description details certain embodiments of the invention.It will be appreciated, however, that no matter how detailed theforegoing appears in text, the invention can be practiced in many ways.As is also stated above, it should be noted that the use of particularterminology when describing certain features or aspects of the inventionshould not be taken to imply that the terminology is being re-definedherein to be restricted to including any specific characteristics of thefeatures or aspects of the invention with which that terminology isassociated.

What is claimed is:
 1. A system for controlling skew in a ball planetarycontinuously variable transmission (CVT) having a plurality of tractionplanets distributed radially about a main axle defining a longitudinalaxis, each traction planet rotatable about an axle defining a tiltableaxis, a first traction ring and a second traction ring in contact withthe traction planets, the plurality of traction planets interposedbetween the first traction ring and the second traction ring, and anidler assembly positioned radially inward of and in contact with each ofthe traction planets, the system comprising: a first stator having aplurality of radial guide slots for engaging a first end of each planetaxle; a second stator having a plurality of radially offset guide slotsfor engaging a second end of each planet axle, the plurality of radiallyoffset slots formed at an angle relative to the plurality of radialguide slots; a stator driver assembly coupled to the first stator,wherein the stator driver assembly comprises a compound planocentricgear set, and wherein the stator driver assembly is configured to rotatethe first stator relative to the second stator; and a timing plate forengagement with one of the first end or the second end of each planetaxle.
 2. The system of claim 1, wherein the plurality of radially offsetguide slots are formed at an angle between 3 and 45 degrees relative toa radial construction line.
 3. The system of claim 2, wherein theplurality of radially offset guide slots are formed at an angle between3 and 20 degrees.
 4. The system of claim 1, wherein the idler assemblycomprises first and second rolling elements.
 5. The system of claim 1,wherein the compound planocentric gear set comprises a fixed ring, anoutput ring, and a compound orbital planet gear.
 6. The system of claim5, further comprising a shifting mechanism coupled to the stator driver,the shifting mechanism comprising an eccentric driver having aneccentric lobe surface that is configured to engage an inner bore of thecompound orbital planet gear.
 7. The system of claim 5, wherein thecompound orbital planet gear comprises a first gear and a second gear,wherein the first gear couples to the fixed ring, and wherein the secondgear couples to the output ring.
 8. The system of claim 6, wherein thestator driver assembly is configured to provide a ratio of 0.01 to 0.05turns of the compound orbital planet gear to about one turn of theeccentric driver, and wherein a positive rotation of the eccentricdriver can result in either a clockwise or a counterclockwise rotationof the output ring gear.
 9. The system of claim 8, wherein the ratiorange comprises 0.01 to 0.05 turns of the output ring gear to one turnof the eccentric driver.
 10. The system of claim 1, wherein the timingplate comprises grooves.
 11. A ball planetary continuously variabletransmission (CVT) comprising: a plurality of traction planetsdistributed radially about a main axle defining a longitudinal axis,each traction planet rotatable about an axle defining a liftable axis; afirst traction ring and a second traction ring in contact with theplurality of traction planets, the plurality of traction planetsinterposed between the first traction ring and the second traction ring;an idler assembly positioned radially inward of and in contact with eachof the plurality of traction planets; and a control system comprising afirst stator having a plurality of radial guide slots for engaging afirst end of each planet axle, a second stator having a plurality ofradially offset guide slots for engaging a second end of each planetaxle, the plurality of radially offset slots formed at an angle relativeto the plurality of radial guide slots, a stator driver assembly coupledto the first stator, wherein the stator driver assembly is configured torotate the first stator relative to the second stator, and a timingplate for engagement with one of the first end or the second end of eachplanet axle.
 12. The CVT of claim 11, wherein the plurality of radiallyoffset guide slots are formed at an angle between 3 and 45 degreesrelative to a radial construction line.
 13. The CVT of claim 12, whereinthe plurality of radially offset guide slots are formed at an anglebetween 3 and 20 degrees.
 14. The CVT of claim 11, wherein the idlerassembly comprises first and second rolling elements.
 15. The CVT ofclaim 11, wherein the stator driver assembly comprises a compoundplanocentric gear set, and wherein the compound planocentric gear setcomprises a fixed ring, an output ring, and a compound orbital planetgear.
 16. The CVT of claim 15, further comprising a shifting mechanismcoupled to the stator driver, the shifting mechanism comprising aneccentric driver having an eccentric lobe surface that is configured toengage an inner bore of the compound orbital planet gear.
 17. The CVT ofclaim 15, wherein the compound orbital planet gear comprises a firstgear and a second gear, and wherein the first gear couples to the fixedring, and wherein the second gear couples to the output ring.
 18. TheCVT of claim 16, wherein the stator driver assembly is configured toprovide a ratio of 0.01 to 0.05 turns of the compound orbital planetgear to about one turn of the eccentric driver, and wherein a positiverotation of the eccentric driver can result in either a clockwise or acounterclockwise rotation of the output ring gear.
 19. The CVT of claim18, wherein the ratio range comprises 0.01 to 0.05 turns of the outputring gear to one turn of the eccentric driver.
 20. The CVT of claim 11,wherein the timing plate comprises grooves.